KK Ajax

Robin
Thanks for posting the plan, etc. In the accompanying article it does say that the rigging 'has attracted considerable investigation by the Shulmanites and offers possibilities provided flier is patient at the trimming stage'. I'll bet!! I still don't understand it. Yes, the tail wold be operating in the downwash from the wing - a fact of life which enabled us to get away with HLGs with 0-0 rigging and the CG at 100%, but even so ......
Mike
Oh - and when you look at the plan you see a small circular mark low on the fus at about 50% chord - that doesn't indicate the CG - it shows where the timer was located.

Oh, and on tail rigging angles. Again back when wolves roamed Wales, many of us flew F/F power duration models with a CG well back (in some cases right at the TE and in a few cases even a little BEHIND the TE). Not being quite that brave I tended to have the CG around 80% back. The tail would be set at around 1 degree positive in relation to the thrustline and the wing at around 2 - 2.5. All this was before folk moved to using variable incidence tailplanes, but the reason was the same - to control the very considerably different lift potential between power on and power off.
There were two schools of thought - the experts, who used the excess lift during power on to create a fast spiral climb, with the looping and rolling tendencies balanced one against the other, and the dummies like me who used a more or less straight vertical climb with the wing's lift more or less out of the equation - the expert's way was more efficient, the dummies way was easier to trim out.
Mike

I'm like you Mike. If I got a spiral climb it was an accident

It's time to get back on-topic!

This one was taking me far too long to get moving, so I invested in a VMC laser-cut kit and I have to say, it was a good decision. The cutting is perfect and the wood selection excellent!

So, after a bit of light sanding on the parts to get rid of the burnt edges, the tailplane and fin were laid down:



...followed by cleaning the burnt edges off the ribs:



...then fuselage joining:



...and a start made on the wings:

Yesterday's work has included lifting the wings off the plan and adding leading edges, tidying of the fin and tailplane outlines and adding some fuselage spacers and joining the sternpost.



It's all off the board now, so stand by for the next project...

Progress today has included fitting the cross pieces and nose fairings to the fuselage and fitting tips and gussets to the wings:

My memories of the Ajax as being bigger than that - but I was only 10 or 11 at the time!

Inspired by your Ajax and the photo I found of my Competitor, and being genuinely snowed in - I have a steep track down to my house which is now an icy waterfall - I've decided to make a 20" span downsized Contestor. Having made similar progress to your Ajax, what surprises me about these models is that they are quite hard to do well. Yes, any kid could stick the bits together and make something that looked like the photo, but it took me ages to get the alignment of the body reasonably square and true from all angles; then there were the wings: under-cambered, double-dihedral, tapering and pointed. Holy Cow! Getting all those faces and angles to align correctly - I still haven't done it that well - is darned hard (IMHO). Little wonder many of us never got these planes to fly well, if at all...!
I will watch your progress with added interest.

Keil Kraft produced a 24” version of the Competitor/Contester in the form of the Eaglet. My Eaglet build thread starts here

www.aeromodellers.co.uk/forum/free-fligh...t?limitstart=0#49441

It may be of help or use with your 20” Competitor build, Crasher. You'll find advice on building and assembling the model, covering it, making the wheels and carving the prop within the thread. The plan is on Outerzone, here:

outerzone.co.uk/plan_details.asp?ID=597

I added Honi Soit Qui Mal Y Pense to the tail of your thread Andy. A nice thread and a nice model. Did you trim it out in the end and did it fly well.Re the wood choice and reinforcement ,the wood in kits in those days tended to being somewhat denser than today I had no probs with crushing formers in the ones I built. Perhaps I was just lucky eh? Is yours still flying. One of mine went into a reservoir and the other was trampled into the mud by sheep.All I could salvage was the nose block and the freewheel .There was another KK cabin job I made It was a very pretty looking plane but I can't recall it's name. Would Ladybird be the name perhaps About 20" span and very semi- scale in appearance but flew quite well with times about the minute mark on average . More or less depending on weather conditions.

John
The Ladybird was a 42" semi-scale - very attractive - for ED Bee or similar.
Mike

one tenor wrote: I added Honi Soit Qui Mal Y Pense to the tail of your thread Andy. A nice thread and a nice model. Did you trim it out in the end and did it fly well.Re the wood choice and reinforcement ,the wood in kits in those days tended to being somewhat denser than today I had no probs with crushing formers in the ones I built. Perhaps I was just lucky eh? Is yours still flying. One of mine went into a reservoir and the other was trampled into the mud by sheep.All I could salvage was the nose block and the freewheel .There was another KK cabin job I made It was a very pretty looking plane but I can't recall it's name. Would Ladybird be the name perhaps About 20" span and very semi- scale in appearance but flew quite well with times about the minute mark on average . More or less depending on weather conditions.

I found it it was a PIXIE in addition I found these links. last one first. www.brchobbies.co.uk/brc_en/customer/address/index/
www.modelflying.co.uk/forums/postings.asp?th=40495&p=2
Pixie plan outerzone.co.uk/plan_details.asp?ID=1375 Also this one of two on Aerofred aerofred.com/details.php?image_id=99230&mode=search

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The other is C/L .As pretty as I recall her.

I'd forgotten the Pixie - doesn't look unlike a scaled down Ladybird
Mike

Apologies for jumping on your thread, but I took advantage of being snowed in by Storm Emma and the Beast from the East and finished my 19" span mini-Conterstor. I tried my first attempt at pre-shrinking the tissue, which had variable results - the wings have a crinkly texture. Also, the artists' fixative I used to seal it reliquified the 'permanent' marker I had used to sharpen the black on white edges. Very annoyed with the staining, which has spoiled an otherwise acceptable outcome. However, I'd rather make this mistake on this plane than on the Sopwith Pup!

It glides almost as straight as an arrow, which is a surprise to me! However, it does have a climbing tendency - perhaps why the original specified a lifting tailplane? I'll fit a noseblock and prop on it soon and give it some juice...

If the model has a climbing tendency, Crashrr, then it's due to the C of G being too far aft or the angle between the wing and tailplane being too big. The 'lifting' tail would have very little to do with it.

I see you've chosen a flat plate tail for your model which, as it happens, is much more efficient than a lifting tailplane on a model of the configuration that you've built.

For the next glide tests, I suggest you either move the C of G forward, or, if it's already on or in front of the main spar, put a sliver of balsa under the leading edge of the tailplane. If the model then pitches up under power, add some down thrust to the nose block by inserting a sliver of balsa between it and the front former at the top.